Nasal irrigation reduces radiation-induced rhinosinusitis in nasopharyngeal carcinoma treated with volumetric modulated arc therapy.

BACKGROUND

Nasopharyngeal carcinoma (NPC), prevalent in Southeast Asia and Southern China, is commonly treated with radiotherapy (RT). Volumetric modulated arc therapy (VMAT) improves tumor control but radiation-induced rhinosinusitis (RIRS) remains a major complication. Nasal irrigation shows potential in mitigating mucosal damage, yet evidence in VMAT-treated NPC patients is limited. This study evaluates Nasal irrigation's efficacy in reducing RIRS incidence in this population.

METHODS

A retrospective cohort of 195 NPC patients treated with VMAT (2018-2021) was analyzed. Patients were divided into Nasal irrigation (n = 84) and non-Nasal irrigation (n = 111) groups. Baseline characteristics and dosimetric parameters (V20-V70, Dmean, Dmax) of the maxillary sinus were compared. Kaplan-Meier analysis and Cox regression models assessed Nasal irrigation's impact on RIRS risk, with subgroup analyses stratified by sex, TNM stage, and treatment regimen.

RESULTS

Kaplan-Meier analysis showed that the probability of developing RIRS was significantly higher in the group that did not undergo nasal irrigation compared with the NI group (p < 0.001). Multivariate analysis confirmed NI reduced RIRS risk (adjusted HR=0.26, p < 0.001), while allergic rhinitis increased risk (adjusted HR=6.56, p = 0.009). For maxillary sinusitis, NI remained protective (HR=0.29, p < 0.001), and higher V70 dose (≥70 Gy) correlated with elevated risk (HR=1.10, p = 0.007). Subgroup analyses demonstrated consistent benefits across sex, T/N stage, and treatment groups (all interaction p > 0.05).

CONCLUSION

NI reduces radiation-induced rhinosinusitis risk in VMAT-treated NPC patients, independent of baseline characteristics. Allergic rhinitis and high V70 doses independently worsen outcomes. These findings support NI as a simple, effective adjunct to improve post-radiotherapy quality of life.